Ribbon guide means for typewriting machines



Nov. 23, 1954 R. M. FORD ETAL RIBBON GUIDE MEANS FOR TYPEWRITING MACHINES Filed Feb. 5, 1952 2 Sheets-Sheet l \NVENTQRS Nov. 23, 1954 R. M. FORD ETAL RIBBON GUIDE MEANS FOR TYPEWRITING MACHINES Filed Feb. 5, 1952 2 Sheets-Sheet 2 |NVEHTORS By mwwmwwm WM; AGENTS.

United rates RIBBGN GUIDE MEANS FOR TYPEWRITING MACELNES Application February 5, 1952, Serial No. 269,996

Claims priority, application Great Britain February 14, 1951 2 Claims. (Cl. 197-170) This invention relates to typewriting machines when used for producing master sheets which are subsequently to be used in a duplicating machine wherein the master sheet bearing the script in reversed type is brought into pressure contact with a suitably moistened copy sheet to reproduce the matter from the master on the copy sheet.

The master sheet is produced by using a special carbon paper known as hectograph carbon which causes considerable marking of the operators hands and it is there fore advantageous to use a ribbon of carbon which requires the rninimum of actual handling by the operator.

The object of the present invention is to provide in or for use with a typewriting machine, new or improved means for guiding the carbon ribbon so that it traverses the proper longitudinal zone of the platen roller and is not displaced laterally by rotation of this roller or is restored when so displaced.

A more specific object of the present invention is to provide improved means for guiding the carbon ribbon which whilst avoiding danger to the type heads should they inadvertently strike it, will allow the master sheet to slide freely thereover when the platen roller is rotated to effect line spacing, and accordingly there is provided in a typewriting machine of the kind having a body, a carriage slidably supported thereon, a platen roller journalled in said carriage, and type heads movable against the platen roller; guide means for the carbon ribbon comprising support members secured to said carriage at opposite ends of the platen roller, and a strip of flexible material including a plurality of elastic strands extending longitudinally of the strip and covered by threads of textile material interleaved transversely with said strands, said strip being supported in tension from said members and extending rectilinearly between same, and lying adjacent to said platen roller parallel to the axis thereof above the carbon ribbon zone.

One of the main advantages of such guide means is that the flexible material especially when in the form of a strip of elastic or rubber may be thin. The paper forming the master sheet may thus conform closely to the surface of the platen roller without great distortion in the carbon ribbon zone, this being important for the proper formation of the carbon lettering or legend in reverse or mirror image upon the face of the master sheet directed towards the platen roller.

Further, the use of a flexible material for the strip or band, such as rubber, avoids damage to the type heads should they inadvertently strike it since such material is generally resilient or absorbent as to impact.

Referring to the drawings:

Figure 1 is a perspective View of a typewriting machine ribbon feed device and guide means showing one construction of the last mentioned in accordance with the present invention.

Figure 2 is a fragmentary view of the arrangement shown in Figure 1 and on an enlarged scale showing the construction and arrangement of the guide means and Figure 3 is a fragmentary view on a still further enlarged scale showing the detailed formation of the guide strip or band.

In the arrangement illustrated in Figure 1 the typewriting machine is of any suitable or usual construction and has a body upon which is slidably supported a carriage 11 in which is journalled a platen roller 12 caatent O or 2,695,091 Patented Nov. 23, 1954 pable of being rotated intermittently by means of hand Wheels 13 to feed a master sheet past the typing station 14 to which the type heads are brought to engage against the platen roller by depression of respective keys 15.

The machine is supported upon a base member 16 having laterally extending side plates 17 and 18 which support respectively a post 19 carrying a dispenser or reel 20 for carbon ribbon of the type known as hectograph carbon and a post 21 housing a take-up mechanism to move the carbon ribbon 22 through the typing station intermittently in synchronism with movement of the carriage 11.

This base member and associated dispenser and takeup device form the subject of our application for patent in the U. S. A. No. 211,927 filed on February 20, 1951, the specification of which contains a full disclosure of these parts, which disclosure will not therefore be repeated in the present specification.

Referring now to Figure 2 of the drawings, guide means for the carbon ribbon 22 comprises supporting members 23 and 24 spaced apart longitudinally of the platen roller 12 so as to lie opposite end zones thereof. These men bers are formed of strip metal and are in the form of brackets having attachment portions 25 and 26 provided with screw holes such as that seen at 27 through which fixing screws as indicated at 28, may be passed to enter tapped holes in a forwardly located longitudinal strip member 29 of the carriage, the lower ends of the supporting members preferably being cranked as indicated at 3% to engage beneath the edge of the member 29.

The supporting members are formed with strip holding portions 31 and 32 of arcuate form which have substantially the same curvature as the platen roller and lie closely adjacent thereto as shown.

Supported by these members or brackets is a guide strip or band 33 held in extended rectilinear formation parallel to the platen roller axis and lying against the surface of the platen roller immediately above the longitudinal zone traversed by the carbon ribbon 22.

This strip or band is held in tension by means of the members 23 and 24 and this may be accomplished either by forming the strip or band of elastic material and spacing the members 23 and 24 apart by a distance greater than its natural length or by forming the strip or band of some relatively inelastic but flexible material such as webbing or tape or a plastic material and applying tensioning means thereto. For example, the members 23 and 24 might themselves be sufficiently resilient to impart the tension.

The preferred form of strip or band is illustrated in Figure 3 in which the strip or band comprises a plurality of strands such as indicated at 34 of rubber or the like elastic material covered by a woven structure or covering 35 consisting of a plurality of cotton or textile threads interwoven with the strands 34 transversely or at right angles thereto. The upper and lower edges 36 and 37 or at least the latter are also preferably of rounded cross section to reduce the tendency for the strip or band to be displaced laterally by the roller when this is rotated. The thread-like covering also tends to reduce such displacement since the threads extend in the direction of rotation and thus present a lower coeflicient of friction between the platen roller and the strip or band in the direction of rotation than they present parallel to the axis of the roller.

For locating and positioning the strip or band positively in its own plane, the holding portions 31 and 32 of the brackets or members 23 and 24 are provided with recessed seatings 38, 39, presenting shoulders such as that shown at 40 affording positive resistance to displacement of the ends of the strip or band in its own plane. These ends may be of looped form as shown at 41 and embrace the holding portions of the support members or brackets.

The latter are further provided with guide passageways for the carbon ribbon 22, such guide passageways being defined, for example, by the provision of loops 42 and 43 through which the carbon ribbon is threaded, these loops extending laterally of the brackets or supporting members beyond the ends of the platen roller.

of excessive tension to the carbon ribbon and despite intermittent rotation of the platen roller. In cases where the strip or band is formed of elastic material, the guide means are automatically self-accommodating with respect to the typewriting machines having platen rollers of differing lengths, the strip or band being stretched to a variable extent depending upon the length of such roller.

What we claim then is:

1. In a typewriting machine of the kind having a body, a carriage slidably supported thereon, a platen roller journalled in said carriage, and type heads movable against said platen roller; the provision of guide means for carbon ribbon comprising, support members secured to said carriage at opposite ends of the platen roller, and a strip of flexible material including a plurality of elastic strands extending longitudinally of the strip and covered by threads of textile material interleaved transversely with 25 said strands, said strip being supported in tension from said members and extending rectilinearly between same, and lying adjacent to said platen roller parallel to the axis thereof above the carbon ribbon zone.

2. In a typewriting machine of the kind having a body, a carriage slidably supported thereon, a platen roller journalled in said carriage, and type heads movable against said platen roller; the provision of guide means for carbon ribbon comprising, support members secured to said carriage at opposite ends of the platen roller, and a strip of flexible material including a plurality of elastic strands of substantially circular cross sectional shape, said strands extending longitudinally of the strip and having a covering of threads of textile material interleaved transversely with said strands, said strip being supported in tension from said members and extending rectilinearly between same and lying adjacent to said platen roller parallel to the axis thereof above the carbon ribbon zone.

References Cited in the file of this patent UNITED STATES PATENTS.

Number Name Date 890,507 Gorin June 9, 1908 2,058,859 Fried Oct. 27, 1936 2,217,180 Noonan Oct. 8, 1940 FOREIGN PATENTS Number Country Date 516,964 Great Britain of 1940 

